Promoted formation of stereocomplex in enantiomeric poly(lactic acid)s induced by cellulose nanofibers

Qian Ren; Minghui Wu; Zhengsheng Weng; Xiuyu Zhu; Wanwan Li; Pengke Huang; Long Wang; Wenge Zheng; Masahiro Ohshima

doi:10.1016/j.carbpol.2021.118800

Promoted formation of stereocomplex in enantiomeric poly(lactic acid)s induced by cellulose nanofibers

Carbohydr Polym. 2022 Jan 15:276:118800. doi: 10.1016/j.carbpol.2021.118800. Epub 2021 Oct 22.

Authors

Qian Ren¹, Minghui Wu², Zhengsheng Weng³, Xiuyu Zhu⁴, Wanwan Li⁴, Pengke Huang⁵, Long Wang⁶, Wenge Zheng⁷, Masahiro Ohshima⁸

Affiliations

¹ Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; Advanced Materials and Composites Department, University of Nottingham Ningbo China, 199 Taikang East Road, Ningbo 315000, China.
³ Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, China.
⁴ Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang Province 315211, China.
⁵ Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
⁶ Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: wanglong@nimte.ac.cn.
⁷ Ningbo Key Lab of Polymer Materials, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: wgzheng@nimte.ac.cn.
⁸ Department of Chemical Engineering, Kyoto University, Katsura, Kyoto 6158510, Japan. Electronic address: oshima@cheme.kyoto-u.ac.jp.

PMID: 34823806
DOI: 10.1016/j.carbpol.2021.118800

Abstract

Stereocomplex (SC) crystallization between enantiomeric poly(_L-lactic acid) (PLLA) and poly(_D-lactic acid) (PDLA) is believed to yield poly(lactic acid) (PLA) with superior physiochemical properties. However, homocrystallization (HC) crystallites are inevitably generated in the PLLA/PDLA blends. Herein, we report a simple approach to fabricate PLLA/PDLA racemic blends with high contents of SC crystallites by introducing cellulose nanofibers (CNFs). The isothermal crystallization results revealed that the half-crystallization time of the PLLA/PDLA blend was significantly decreased by adding CNFs. Additionally, with the incorporation of 3 wt% modified CNFs, the PLLA/PDLA blend was overwhelmingly crystallized into SC crystallites with no HC crystallite formation. Based on Fourier transform infrared spectroscopy findings, it was speculated that the preferred SC crystallization of PLLA/PDLA/CNF was caused by enhanced interchain molecular interactions between CNFs and PLA. This work presents a feasible and efficient method to fabricate PLA with exclusively SC crystallites, which possesses great potential for producing high-performance PLA materials.

Keywords: Cellulose nanofibers; Hydrogen bonding; Poly(lactic acid); Stereocomplex.